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使用泛型迭代Map集合

    博客分类:
  • java
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package com.bird.beanutils;

import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;
import java.util.Map.Entry;

import org.junit.Test;

/**
* @use 使用泛型对Map进行迭代
* @author Bird
*
*/
public class DemoMap {
    
    @Test
    public void test1(){//对Map进行迭代
        Map<Integer,String> map = new LinkedHashMap<Integer,String>();
        map.put(1, "one");
        map.put(2, "two");
        map.put(3, "three");
        map.put(4, "four");
        map.put(5, "five");
        map.put(7, "seven");
        
        //传统EntrySet迭代
        Set<Map.Entry<Integer, String>> set = map.entrySet();
        Iterator<Entry<Integer, String>>  it = set.iterator();
        while(it.hasNext()){
            Map.Entry<Integer, String> entry = it.next();
            int key = entry.getKey();
            String value = entry.getValue();
            
            System.out.println("key" + " "+ key + "\n"+"value" + " "+ value);
        }
    }
    
    
    @Test
    public void test2(){//使用增强for循环
        Map<Integer,String> map = new LinkedHashMap<Integer,String>();
        map.put(1, "one");
        map.put(2, "two");
        map.put(3, "three");
        map.put(4, "four");
        map.put(5, "five");
        map.put(7, "seven");
        
        for(Map.Entry<Integer, String> en : map.entrySet()){
            int num = en.getKey();
            String value = en.getValue();
            
            System.out.println(num + "==" + value);
        }
        
    }
}
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